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<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
<head>
<style>
p.normal {
font-weight: normal;
}  
p.light {
font-weight: lighter;
}
p.thick {
font-weight: bold;
}
p.thicker {
font-weight: 900;
}
</style>
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<body>
    <p class="normal">段落</p>
    <p class="light">段落</p>
    <p class="thick">段落</p>
    <p class="thicker">段落</p>
</body>
</html>